The present invention relates to a disk brake for an elevator drive, the brake having brake levers with brake linings, compression springs, and a brake magnet, the brake levers being caused by the force of the compression springs to act through the brake linings on a brake disk and bring the elevator drive to a standstill, and the brake levers being released by the brake magnet acting on the brake levers against the force of the compression springs.
The European patent specification EP 0 535 344 shows a disk brake that acts on a brake disk of an elevator drive, the symmetrically constructed disk brake thereby bringing the elevator drive to a standstill. Two brake levers are pivoted on a rigid supporting bracket. Each brake lever has two arms, there being arranged at one end of the brake lever a brake shoe with a brake lining that acts on the brake disk when braking occurs. Acting on the other end of the brake lever is a compression spring that is supported on a stop and on the brake lever. The compression spring of the second brake lever is also supported on the stop, the stop being movably held in a brake magnet. If the stop moves due to, for example, breakage of a compression spring, a sensor generates an alarm signal. To release the disk brake, the brake magnet, which is fitted with an armature plate, is activated, the brake magnet with the armature plate thereby acting against the force of the compression springs.
A disadvantage of this known device is that the disk brake with its centrally arranged brake magnets is of relatively wide construction and therefore not suitable for situations where space is restricted.
The present invention provides a solution to avoiding the disadvantages of the above-described known device and creating an elevator drive with a disk brake of narrow construction which can also be easily released manually.
The advantages achieved by the present invention are that the elevator drive can be constructed in modular manner. The elements of the symmetrically constructed brake device are arranged outside the motor area. The motor is therefore easily accessible and easily replaceable. The elements of the brake device are simply constructed and inexpensive to manufacture. The brake device is redundant, and also functions with one brake lever. The single-arm brake levers permit the structure of the elevator drive to be shorter. Furthermore, the brake device can be remotely operated by hand by means of, for example, a Bowden cable. The elements of the brake device are well accessible and easily replaceable. For disassembly it is only necessary to remove the compression springs. The brake device can then be removed upwardly. Maintenance (checking the brake linings, the air gap of the magnet, the parallelism between the brake magnet and armature plate, and the spring pretensioning) is simplified by the brake device according to the present invention. Because the brake device acts directly on the traction sheave, the brake device can be used as a protective device against overspeed of the elevator car in the upward direction.